The present invention relates generally to railway coupler connections and more particularly to an improved arrangement for retention of a slackless coupler member in which the longitudinal draft loads of the coupler member are distributed over a larger area allowing for reduced concentration of stress in the center sill and the coupler member connection.
Railway cars are connected together by coupler members, namely drawbars or couplers. Drawbars are integral units known to be used in the railroad industry to extend between and permanently connect two or more railcars. Couplers are independent units in each car which interconnect with one another between adjacent cars, to form a connection. In either instance, a shank and butt end of the drawbar or coupler extends into the center sill of a railway car where it is secured to transmit longitudinal loads to the car.
One type of drawbar is currently positioned and held within the center sill of a railway car by the combination of a draft key inserted through a pair of sill side castings. Such an arrangement is shown in Altherr et al, U.S. Pat. No. 4,700,853 wherein the sill side castings have inward projections to center the drawbar within the center sill. In addition to laterally positioning and holding the drawbar, the sill side castings have also fully encircled the draft key so as to transfer the longitudinal loads, particularly the draft load, of the drawbar from the draft key to the center sill.
One problem with this arrangement is that the surface area for draft load distribution between the horizontal draft key and the sill side castings is limited to the small arcuate edge portions of the draft key which are in contact with the sill side castings. This results in a high concentration of stress which can lead to fatigue and failure. It has therefore been necessary that the sill side castings be rigidly secured (heavily welded) to the inside of the center sill so as to withstand the longitudinal draft loads of the drawbar.
It is advantageous in operating a railroad to have railway cars which can be converted from a drawbar arrangement to a coupler arrangement. Accordingly, it is desirable to have a drawbar retention arrangement that is removable. However, the only way to remove the sill side castings is to burn off the heavy welding on the inside of the center sill. Burning off this heavy weld is extremely difficult and often causes damage to a portion of the center sill side wall which must be restored or replaced. This procedure is costly and time consuming.